With the balls actually having nothing to do with it, but initially thought by others to have been the use of the balls to produce the magical sound ball clankin creates. It is an action where your slap your dick against your stomache, preferably when it's wet out of the shower, to get the nice clankin noise that it produces to piss off your roommates early in the morning.

"Hey P you french bastard, prepare for some early morning ball clankin'"